Nanoparticulate materials, and methods for making nanoparticulate materials, have been the subject of recent interest and research because of the advantages provided by nanoparticulate materials over larger sized particulate materials. One advantage of nanoparticulates is increased surface area, which is useful in a variety of applications, including catalyst, electrocatalyst, absorbent, chemical separations and bio-separation applications. Nanoparticulates are also useful in formulations of inks, pastes and tapes that are used in depositing thin or thick films, such as optically transparent conductors for use in displays, magnetic coatings for storage media and printed circuitry for electronic applications. Inks and pastes with nanoparticulates have improved rheology characteristics (e.g., flowability), which allow thinner layers to be applied and allow deposition of features with smaller dimensions. Lighting applications also benefit from the properties of nanoparticulate materials; for example, semiconductor nanoparticulates, in addition to other uses, are useful because of their “quantum dot effect,” which allows the luminescent color of a semiconductor nanoparticulate to be tailored according to the size of the nanoparticulate. In addition to the examples above, nanoparticulate materials are being used, or considered for use, in many other applications including pharmaceutical formulations, drug delivery applications, medial diagnostic aids, abrasives, pigments, phosphors for lighting, dental glasses, polymeric fillers, thermal interface materials and cosmetics.
As a result of the large number of applications for nanoparticulate materials, a variety of methods have been developed for making and processing nanoparticulates. One common problem faced by these methods is the tendency of the nanoparticulates to agglomerate because of their high surface area. Once the nanoparticulates have agglomerated, often they do not provide the same advantages achieved when the individual nanoparticulates are in a dispersed state. Consequently, the tendency of nanoparticulates to agglomerate makes the forming, processing, handling, transporting and use of nanoparticulates problematic. Complicating matters is that separating or redispersing nanoparticulates once they have agglomerated is difficult to do.
Thus, there is a need for additional methods of forming, processing, handling, transporting and using nanoparticulates and new nanoparticulate products that alleviate some or all of these problems.